fix(ci): isolate publish concurrency by event type

Dev publishes (push to main) and stable releases now use separate
concurrency groups so a dev publish can never cancel an in-progress
release, and vice versa.

Author: github-actions[bot]

.github/workflows/publish.yml

@@ -13,7 +13,7 @@ on:
         type: string
 
 concurrency:
-  group: publish
+  group: publish-${{ github.event_name }}
   cancel-in-progress: true
 
 permissions: {}